A. Field of the Invention
The present invention relates to a focusing and defocusing mechanism for a digital camera, especially to a spring-free type focusing and defocusing mechanism which can simplify the structure of a digital camera lens.
B. Description of the Prior Art
The focusing and defocusing mechanism for a conventional digital camera usually adopts cam ring and spring structure. As illustrated in FIG. 1, the cam ring and spring structure requires lots of parts. The front lens barrel 13, an aperture stop 16, a cam barrel 12, a spring set 11 , a lens holder 14, and a rear lens holder 15 are arranged in an optical axis.
The function of focusing and defocusing relies on the mechanism of the spring set 11, and the cam barrel 12. The elasticity of the spring set 11 allows the front lens barrel 13 and the cam barrel 12 to shift back and forth along the optical axis of the camera lens barrel. Based on this focusing and defocusing mechanism, the entire structure of the lens barrels is relatively complicated. The complexity of the entire structure inevitably increases the manufacture cost and the time in assemble and maintenance. It also makes the size of the camera difficult to reduce.